Current Situation: 
Influenza activity significantly decreased from week 1 through week 4; however, a slight increase in activity was observed over the past two weeks. Influenza activity is expected to continue through May and Orange County residents are encouraged to be vaccinated if they still haven’t received the 2017-18 vaccine. To date, 74 severe cases of influenza (less than 65 years of age and hospitalized in intensive care or who died) have been reported in Orange County; 12 of the 74 severe cases were influenza-associated deaths. Influenza A(H3) overall has been the most frequently identified influenza virus but A(H1N1) and B strains have also been reported.  Of note, the proportion of influenza reports that are type B (blue bar in graph) has increased over the past few weeks.